import java.util.Scanner;
class first {
    public static void main(String[] args) {
        System.out.print("输入第一个数：");
        double num1=new Scanner(System.in).nextInt();
        System.out.print("输入第二个数：");
        double num2=new Scanner(System.in).nextInt();
        System.out.print("输入运算符：");
        String a=new Scanner(System.in).next();
        double result=0;
        switch(a){
            case "+":
                result=num1+num2;
                System.out.print(result);
                break;
            case "-":
                result=num1-num2;
                System.out.print(result);
                break;
            case "*":
                result=num1*num2;
                System.out.print(result);
                break;
            case "/":
                if(num2==0)
                {
                    System.out.print("数字2输入错误");
                }
                else{
                    result=num1/num2;
                    System.out.print(result);
                }
                break;
            default:
                System.out.print("输入错误");
                break;
        }
    }
}